Brake



19417 7 H. c. SWIFT 2,242,685

' BRAKE Fil-gd May 18, 1939 u 82 62 aa 64 t x 60 J 64 2 20 H I N VEN TOR. T 92- BY ATTORNEY.

Referring to Patented Ma 20, 1941 UNITED STATES PATENT OFFICE 2,242,685 I j Y BRAKE Harvey 0. Swift, Detroit, Mich., assignor to Bydra'ulic Brake Company, Detroit, Mich., a corporation of California 7 Application May 18, .1929, Serial No. 274,463

5 Claims. (01. 188-195) This invention relates to brakes, and more particularly to means for adjusting the friction elements of brakes.

An object, of the invention is to provide means for automatically adjusting the friction elements of a brake.

Another object of the invention is to provide an automatic adjuster-for the friction element of a brake controlled by wear on the lining of the friction element.

Another object of the invention is to provide an automatic adjuster for a brake operative to adjust the friction .element ofthe brake proportionately to wear on the lining of the friction element so that the friction element may be supported in proper spaced relation to the drum' when in retracted position.

Other objects of the invention will appear from the'following description taken in connection with the drawing forming a part of this specification, and in which,

Fig. 1 is a vertical sectional view of a brake embodying the invention; and

Fig. 2 is an enlarged longitudinal sectional view.

the drawing for more specific details of the .invention, l8 represents a fixed support or backing plate adapted to be secured to an axle or to an axle housing, and associated with the backing plate is a rotatable drum l2 adapted to be secured to a'wheel.

The backing plate has arranged thereon spaced anchors l4 and I8, and a fluid pressure actuated motor indicated generally at l8. A pair of corresponding interchangeable friction elements -or shoes 28 and 22 suitable for cooperation with the drum have their articulate ends pivoted on the anchors. The force applying ends of the shoes are connected to the motor l8, and a-re-' tractile spring 24 connects the shoes adjacent their force applying ends. The shoes may be of any desirable type. Preferably each of the shoes includes a web 26 supporting a rim 28 having secured thereto a friction lining 38 suitable for cooperation with the ,drum l2.

The motor I8 [includes a cylinder 32 open at both of its ends and provided substantially centrally of its length with a port 34 adapted to be connected to a suitable source of fluid pressure.

The cylinder has therein opposed -reciprocable pistons 36 and 38 having on their heads sealing cups 48 and 42 held against displacement by a spring 44 interposed between the cups.

Adjusters 48 and 48 associated with the pistons 38 and 38 are'operative to automatically adjust the friction elements 28 and 22 with relation to the drum l2. As'shown, each of the pistons includes a body portion 58 having a flange 52 adapted to abut the adjacent end of the cylinder when the piston is in retracted position. The piston has a concentric groove or channel 54, the purpose of which will hereinafter appear,

7 and an axial bore '56 having therein a partition 58 provided with a frustro-conical-opening 68.

A sleeve 82 threaded in the outer end of the bore 58 has a circumferential flange 84 received by a slot 66 in the web of the adjacent shoe,'and the sleeve is secured against rotation by a slot 68 in the flange cooperating with the web. A

torsion spring I8 slipped int the concentric channel 54 in the piston has one of its ends connected tothe flange 84 and its other end secured to the piston in the bottom of the channel. This spring normally tends to rotate the piston within the cylinder.

A rod I2 reciprocable in the sleeve I52 has on one end a conical head 14 adapted to seat in the conical opening 88 in thepartition 58, and

a plug 16 secured in the inner end of the axial I bore 56 closes the inner end of the bore so as to complete the face of the piston to provide an unbroken surface or seat for the associated sealing cup. The rod has thereon a collar 18 and a spring 88 interposed between the collar and a ring 82 fixedly securedto the web of the I shoe and encompassing the rod. The spring 88 urges. the rod outwardly so as to seat the head 14 in the opening 68 wherein the head; I4 fric tionally holds the piston against rotation.

The outer end of the rod has, thereon a head 84 slidable in an opening through the rim 28 and lining 3 8 ofthe shoe, and suitably secured to the head 84 is. a liriing 88 having a coeflicient of friction lower than that of the lining on the shoe.

In a normal operation, upon energization of the fluid pressure actuated motor l8, the friction elements or shoes 28 and 22 are moved into engagement with the drum l2 against the resist ance of the retractile spring 24 toretard. rotation of the drum. In effecting this operation, the pistons 38 and 38 of the motor l8 are moved in opposite directions, and force is transmitted; from the pistons through the sleeves 82 threaded in the outer ends ofthe pistons to the forceapplying ends of the shoes 28 and 22' to engage the friction linings 38 'on the shoes. with the drum. I v

During this operation, the adjusters 48 and 4 48 carried by and movable with the pistons are moved to engage the' linings 88 thereon with the the adjuster, and during this movement the rod 12 is moved against the resistance of the spring 80. This results in moving the head 14 on the inner end of the rod from its seat in the conical opening ll, whereupon the torsion spring 10 becomes effective to rotate the piston. As the piston rotates, it travels on the threaded sleeve 62, so asto take up clearance and again seat the head I. in the opening 6. where it is held by the spring 80 and frictionally holds the piston against rotation.

The operation just described results in extending the overall length of the piston and moving the head 8. on the adjuster in the opening 86 through the vrim 28 and lining 30 of the shoe' so that the lining 83 on the head 84 of the adjuster is contiguous with the lining on the shoe, hence, upon conclusion of a. braking operation andreturn of the friction elements or shoes to retracted position under the influence of the retractile spring 24, theshoes are supported by the sleeves 82 threaded in the outer 'ends of-the pistons in proper spaced relation to drum.

the

while this invention has been described in connection with certain specific embodiments,

the principle involved is susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is,

therefore, to be limited only as indicated by the scope of the appended claims.

Having thus described the various features of the invention, what I claim as'new and desire to secure by Letters Patent is:

1. A brake comprising a fixed support, a rotatable drum associated therewith, a pair of friction elements on the support having linings ,for cooperation withthe drum, means for actuating the friction elements including a cylinder, opposed extensible pistons'reciprocable in the cylinder,.means for extending the pistons pro- DOrtionately to wear on the linings and means cooperating with the drum for control of the go means for extending the pistons. a

2. A brake comprising a rotatable member, a friction element for cooperation with the rotatable member, an actuator for the friction element including an extensible piston, means for extending the piston, means for control of the.

means for extending the piston, and means cooperating with the rotatable member to release the control means I 3. A brake comprising a rotatable member, a friction element for cooperation with the rotatable member, an actuator for the friction ele-.

ment including a cylinder, an extensible piston reclprocable therein, means tending to extend the piston, means for control of the means tending to extend the piston and means cooperating with the rotatable member for governing the ,control means.

.A. 'A brake comprising a rotatable drum, a friction element for cooperation with the drum, an actuator for the friction element including a cylinder, an extensible piston reciprocable in the cylinder, a torsion spring tending to extend the piston, a friction holding means for control ofthe spring, and means cooperating with the drum for controlling the holding means.

5. A brake comprising a fixed support, a rotatable drum associatedtherewith, a pair of friction elements on the support for cooperation with the drum, an actuator for the friction elementsincluding a cylinder, opposed extensible pistons reciprocable in the cylinder, torsion springs .tending to extend the pistbns, friction holding means controlling the springs, means cooperating with the drum for releasing the holding means, and means tending to engage the holding means.

6. A brake com'prisinga fixed support, a rotatable drum asociated therewith, a pair of friction elements on the support for cooperation with the drum, an actuator for the-friction elements including a cylinder, opposed pistons reciprocable in the cylinder having relatively movable parts, stops determining the retracted positions of the pistons, torsion springs tending to extend the pistons, friction holding means for control of. the springs, means cooperating withthe drum for releasing the holding means, and means tending to engage the holding means;

HARVEY C, SWIFT. 

